New Approach for Multiphase-Flow Rate and Pressure Transient Analysis in Hydraulically Fractured Porous Media: Deterministic Models for Reservoir Total Mobility and Compressibility

2018 ◽  
Author(s):  
Salam Al-Rbeawi ◽  
Jalal Owayed
Keyword(s):  
Porous Media ◽  
Multiphase Flow ◽  
Flow Rate ◽  
Transient Analysis ◽  
Fractured Porous Media ◽  
Deterministic Models ◽  
Pressure Transient Analysis ◽  
New Approach ◽  
Pressure Transient

Delivering Pressure Transient Analysis During Drawdown on ESP Wells: Case Studies and Lessons Learned

2021 ◽  
Author(s):  
Lawrence Camilleri ◽  
Mohammed Al-Jorani ◽  
Mohammed Kamal Aal Najar ◽  
Joseph Ayoub
Keyword(s):  
Real Time ◽  
Case Studies ◽  
Flow Rate ◽  
High Frequency ◽  
Transient Analysis ◽  
Continuous Production ◽  
Complete Analysis ◽  
Pressure Transient Analysis ◽  
Pressure Transient ◽  
Production History

Abstract While pressure transient analysis (PTA) is a proven interpretation technique, it is mostly used on buildups because drawdowns are difficult to interpret. However, the deferred production associated with buildups discourages regular application of PTA to determine skin and identify boundary conditions. Several case studies are presented covering a range of well configurations to illustrate how downhole transient liquid rate measurements with electrical submersible pump (ESP) gauges enable PTA during drawdown and therefore real-time optimization. The calculation of high-frequency transient flow rates using ESP gauge real-time data is based on the principle that the power absorbed by the pump is equal to that generated by the motor. This technique is independent of fluid specific gravity and therefore is self-calibrating with changes in water cut and phase segregation. Analytical equations ensure that the physics is always respected, thereby providing the necessary repeatability. The combination of downhole transient high-frequency flow rate and permanent pressure gauge data enables PTA using commonly available analytical techniques and software, especially because superposition time is calculated accurately. The availability of continuous production history brings significant value for PTA. It makes it possible to perform history matching and to deploy semilog analysis using an accurate set of superposition time functions. However, the application of log-log analysis techniques is usually more challenging because of imperfections in input data such as noise, oversimplified production history, time-synchronization issues, or wellbore effects. These limitations are solved by utilizing high-frequency downhole data from ESP. This is possible first as superposition time is effectively an integral function, which dampens any noise in the flow rate signal. Another important finding is that wellbore effects in subhydrostatic wells are less impactful in drawdowns than in buildups where compressibility and redistribution can mask reservoir response. Key reservoir properties, in particular mobility, can nearly always be estimated, leading to better skin factor determination even without downhole shut-in. Finally, with the constraint of production deferment eliminated, drawdowns can be monitored for extended durations to identify boundaries and to perform time-lapse interpretation more efficiently. Confirming a constant pressure boundary or a change in skin enables more effective and proactive production management. In all cases considered, a complete analysis was possible, including buildup and drawdown data comparison. With the development of downhole flow rate calculation technology, it is now possible to provide full inflow characterization in a matter of days following an ESP workover, without any additional hardware or staff mobilization to the wellsite and no deferred production. More importantly, the technique provides the necessary information to diagnose the cause of underproduction, identify stimulation candidates, and manage drawdown.

A Practical Implementation of Pressure Transient Analysis in Leak Localization in Pipelines

2004 ◽  
Author(s):  
H. A. Warda ◽  
I. G. Adam ◽  
A. B. Rashad
Keyword(s):  
Numerical Model ◽  
Flow Rate ◽  
Transient Analysis ◽  
Leak Detection ◽  
Valve Closure ◽  
Pressure Transient Analysis ◽  
Pressure Transient ◽  
Pressure Transients ◽  
Pipeline Flow ◽  
Detection And Localization

In the present study, a more realistic approach for using pressure transient analysis in leak detection and localization is proposed. In a previous publication [1] by the authors, the feasibility of using pressure transients, generated by full closure of a downstream solenoid control ball valve, in leak detection and localization is investigated. The main shortcoming of using the full closure of a downstream valve is the very high pressure rise that may reach 14 times the operating pressure. Also, full valve closure yields to discontinue the whole pipeline flow. In the present paper, a controlled partial downstream or upstream valve closure is used as a mean of generating pressure transients to overcome the above drawbacks. The percentage of the valve closure is controlled to reduce the pipeline flow rate by 20–80%. Pressure transients generated by a partial valve closure are investigated experimentally and numerically. The experimental setup consists of a 60 m long and 25.4 mm internal diameter PVC pipelines connecting two tanks. Leaks are simulated at different locations along the pipeline to investigate the effect of leak positions. The pressure time history is recorded using piezoelectric pressure transducers located at five equidistance points along the pipeline connected to a Data Acquisition System. Experiments are carried out for different leak quantities ranging from 2% to 20% of the pipe flow rate. The numerical model accounts for complex pipe characteristics, such as unsteady friction and viscoelastic behavior of pipe walls. The leak is treated as a flow through an orifice of prescribed size. The numerical model is experimentally verified to insure the capability of the model in accounting for unsteady and viscoelastic complex phenomena and efficiently simulating pressure transients in the presence of a leak.

Pressure-Transient Analysis of Bottomhole Pressure and Rate Measurements by Use of System-Identification Techniques

SPE Journal ◽  
2015 ◽  
Vol 20 (05) ◽  
pp. 1005-1027 ◽  
Author(s):  
M.. Mansoori ◽  
P. M. Van den Hof ◽  
J.-D.. -D. Jansen ◽  
D.. Rashtchian
Keyword(s):  
System Identification ◽  
Frequency Domain ◽  
Flow Rate ◽  
Transient Analysis ◽  
Closed Loop ◽  
Reservoir Model ◽  
Data Set ◽  
Pressure Transient Analysis ◽  
Pressure Transient ◽  
Piecewise Constant

Summary This study presents a novel perspective on pressure-transient analysis (PTA) of downhole-pressure and flow-rate data by use of system-identification (SI) techniques as widely used in advanced process engineering. Key features of the paper are that it considers the classic PTA process from a system-theoretical perspective; derives the causal structure of the flow dynamics; proposes a method to deal with continuously varying pressure and flow-rate signals contaminated with correlated noise, which estimates physical reservoir parameters through a systematic matching procedure in the frequency domain; and can cope with arbitrary (i.e., not necessarily piecewise constant) flow-rate signals. To this end, the wellbore and the reservoir are modeled as two distinct two-port power-transmitting systems that are bilaterally coupled at their common boundary. This structure reveals that, from an SI perspective, the wellbore dynamics affect the bottomhole data as a feedback mechanism. Because of this feedback structure, it is necessary to use closed-loop SI techniques, and, because of the presence of sensor noise, the reservoir model cannot be identified solely from the bottomhole measurements. Therefore, an auxiliary signal is needed, for which we choose the surface flow rate, although other signals, such as the bottomhole temperature, could potentially also be used. Then a suitable closed-loop SI technique is the so-called two-stage method. The first stage of the algorithm removes the dynamic effects of the wellbore from the noisy data, and the second stage identifies the reservoir model in terms of rational polynomials. Thereafter, the usual physical reservoir parameters (e.g., averaged permeability and skin factor) are obtained through matching the results of the identified reservoir model and those of typical analytical reservoir models in the frequency domain, as an alternative to classic graphical or numerical type-curve analysis. The method does not rely on a piecewise constant approximation of the flow-rate signal, unlike other known PTA methods such as time-domain deconvolution. Six numerical experiments, by use of a synthetic data set, and one field example, by use of data from a real gas well, illustrate the key aspects of the proposed method.

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